New pyrazole-thiadiazole Schiff derivatives: synthesis, characterization and pharmacological evaluation

Abstract This study reports the synthesis, characterization and pharmacological evaluation of novel series of 1,3,4-thiadiazole containing pyrazole Schiff base heterocycles. The structural elucidation of the synthesized compounds was performed using 1H and 13C NMR spectroscopy, mass spectrometry (MS) analysis, Fourier Transform Infrared spectroscopy (FT-IR) analysis. The antibacterial activity, antioxidant potential and cytotoxicity studies of newly synthesized compounds were assessed. The compound 8a exhibiting most potent inhibitory effect against S. aureus and E. coli with inhibition zones of 20 and 18 mm, respectively, at 50 µg/mL. The antioxidant potential of the compounds was evaluated using DPPH radical scavenging assay and FRAP assay which envisioned that the compounds 8a, 8c, and 8d showed highest potency. Cytotoxicity studies conducted on triple-negative breast cancer (MDA-MB-231) and estrogen receptor-positive breast cancer (MCF-7) cell lines showed that compound 8c exhibited the strongest anticancer activity with 65.29% inhibition against MDA-MB-231 and 54.36% of inhibition against MCF-7 cell line at 1000 µM concentration. These findings suggest that these hybrid heterocycles hold significant promise as potential candidates for antimicrobial, antioxidant and anticancer applications. GRAPHICAL ABSTRACT